Prefix http/https for URLs to screenshot

Access to fetch at 'https://backend-screenshot-to-code.onrender.com/api/screenshot' from origin 'https://picoapps.xyz' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.